1. Field
The present general inventive concept relates to a cloud system, a method of controlling the system, a management server and a method of controlling the server, and more particularly, a cloud system, a method of controlling the system, a management server and a method of controlling the server, capable of copying data, which is stored in one of a plurality of cache servers included in the cloud system, into another cache server.
2. Description of the Related Art
A cloud system refers to a computing system, which allows IT-related services, such as data storage, networking, use of contents, etc., to be used at the same time through a server on the Internet.
The cloud system includes computing environments, in which information is permanently stored in a server on the Internet and temporarily stored in a client, such as an IT device, examples of which may include a desktop computer, a tablet PC, a notebook, a netbook, a smart phone, etc. That is, any information, including document files, image files, audio files, etc., may be stored in the server on the Internet, such that the user can use the information anytime and anywhere, through various types of IT devices.
In other words, the cloud system is a computing service provided in such a manner that a user borrows usage space of computing sources, such as hardware, software, etc., without making these computing sources physically available to the user. In return for this cloud space usage, the user pays for the use, namely, denotes a technology of providing computing resources, which exist in different physical positions, in an integrating manner through a visualization technology. The cloud computing, which is an innovative computing technology providing IT-related services, such as data storage, networking, use of contents, etc., at the same time through a server on an Internet, which is represented as a cloud, is also defined as “a customized out-sourcing service of IT resources using an Internet.”
Recently, with an increased use of the cloud system, auto scaling using load balancing, which is an inherent function of the cloud system, is necessarily employed.
Here, the load balancing refers to a technology of distributing data processing requested by users when the requests exceed a resource (i.e., a resource, such as CPU, memory, etc. to execute data processing requests) of an application server, which is executing a task in response to the users' requests in the cloud system.
Also, the auto scaling refers to a technology of processing exceeded user requests in such a manner of allowing another application server to support an insufficient resource.
For example, in auto scaling in when 150 clients request that data processing be performed in a first application server that only includes sufficient resources to execute data processing requests of 100 clients per a unit time, a resource (i.e., a resource, such as CPU, memory, etc. to execute data processing requests) of a second application server in a client system is therefore provided.
Further, a conventional caching service is also applied to a cloud system. The caching service refers to a technology of shortening a response time with respect to a user request in a manner of storing data, which a user frequently searches to find, in a separate cache server, other than a cloud database.
That is, a first cache server supporting a first application server, which has initially performed a task in response to a user's request, stores beforehand contents which the user frequently searches to find. Then, when a user request regarding the contents is input, the first application server accesses the first cache server, instead of the database within the cloud system, to respond to the user request.
Afterwards, data processing requested by a user exceeds a resource of the first application server, a resource of a second application server, which is located in the cloud system, may be provided by load balancing and auto scaling. However, since a second cache server supporting the second application server has not stored information related to the contents frequently searched by the user, a response time with respect to the user request may extend.
That is, since a second cache server supporting the second application server has not stored information related to the contents frequently searched by the user (i.e., contents with a high hit rate), it may take a long time to store information related to a hit rate corresponding to specific data of a user and the data with a high hit rate in the second cache server providing a caching service to the second application server. Accordingly, data is instead received by directly accessing a database via the cloud system, which may also result in an extended response time with respect to a user request.